When I was growing up, no one knew from vegetarian burgers. Today, they've become big business, as more and more health-conscious Americans adopt at least partial vegetarian diets. The following recipe combines mushrooms, oats and brown rice into a patty that looks somewhat like a hamburger and has a rich, earthy flavor that could almost be described as meaty. It's also a great way to use up leftover brown rice. Note that vegetarian burgers are more fragile than beef or lamb burgers. Cook them on a well-oiled vegetable grate and turn as gently as possible with a spatula.

For the burgers:

• 2 tablespoons olive oil
• 1 medium onion, finely chopped
• 2 cloves garlic, minced
• 8 ounces white mushrooms, wiped clean with dampened paper towels and finely chopped
• 1 cup cooked brown rice
• 1/2 cup quick oats
• 4 ounces coarsely grated sharp Cheddar cheese (about 3/4 cup)
• 1 egg, lightly beaten
• Salt and freshly ground black pepper, to taste
• 2 to 3 tablespoons fine dry bread crumbs, if needed

• 1 large fresh, ripe tomato, thinly sliced
• 1 large onion, thinly sliced (optional)
• Pickle slices
• 1/2 head iceberg lettuce, thinly sliced
• 4 whole-wheat hamburger buns
• Ketchup and/or mayonnaise and/or mustard

1. Prepare the burger mixture. Heat the oil in a nonstick skillet over medium heat. Add the onion and garlic and saute until soft but not brown, about 4 minutes. Increase the heat to medium-high, add the mushrooms, and cook, stirring occasionally, until tender and most of the mushroom liquid has evaporated, about 4 minutes.

2. Stir in the brown rice and cook for 1 minute. Remove from heat and transfer the mixture to a large bowl. Stir in the oats, cheese and egg. Add salt and pepper. If the mixture seems wet, add the bread crumbs. Cover the mixture and refrigerate until firm, 3 to 4 hours.

3. Line a baking sheet or large plate with plastic wrap. Wet your hands slightly and form the vegetable mixture into 4 patties. Place the patties on the prepared baking sheet, cover loosely with plastic wrap, and refrigerate for 1 hour.

4. Preheat grill to high.